Rubber-friction draft gear



Jan. 5, 1960 EgH. BLATTNER RUBBER-FRICTION DRAFT GEAR Filed March 5l, 1958 .ma` l2 /336 3s BY ELIZABETH BLATTNER, EXECUTRIX By adi Wg' his Atorney arent Oiiiee 2,919,819 Patented Jan. 5, 1960 RUBBER-FRICTION DRAFT y GEAR Emil H. Blattner, deceased, late of Williamsville, N.Y.,

by Elizabeth Blattner, executrix, Rochester, N.Y., assignor to Symington Wayne Corporation, Salisbury, Md., a corporation of Maryland Application March 31, 1958, Serial No. 724,949

7 Claims. (Cl. 213-39) This invention relates generally to draft gears for railway Vehicles and particularly to a combined rubber and friction draft gear in which the several cushioning units are contained in a housing.

With the increase in recent years in the length and speed of trains and the speed at which cars are coupled in classification yards, it has become increasingly apparent that the capacities of draft gears must be increased, particularly in buff. As a solution for the problem, it has been proposed to increase the length of a draft gear pocket, now standardized by the A.A.R. at 24%, to some 36, in order to accommodate a longer and correspondingly higher capacity draft gear. However, even if approved, this solution would apply only to new cars and be of no help to existing cars fitted with the present standard pockets.

The cushioning devices in use or proposed for the present standard draft gear pocket are of three general types, one a housed friction draft gear, another a single or plurality of unhoused rubber cushioning units, and the third a housed gear containing both rubber and friction cushioning units. Of the three, the second or rubber type utilizes rubbers high resistance to compression as it approaches its permissive compressive limit of some 45% to obtain high ultimate capacity but, due to the low gradient of the capacity curve of rubber over the initial and intermediate stages of compression, has a low capacity over most of the range of travel. In the first or friction type, the capacity increases substantially in proportion to-the travel, giving good performance over initial and intermediate ranges, but a much lower ultimate capacity than the rubber type. Although meeting present A.A.R. standards which permit a minimum ultimate capacity for a cushioning device ittable into a standard pocket of only about 18,000 foot pounds, neither the rubber nor the friction type approaches the operating characteristics estimated to be needed for fully satisfactory performance under present and contemplatedl service conditions.

While theoretically better than the other types in obtaining increased capacity at partial travel from its friction means and deriving high ultimate capacity from its rubber, the third type, as heretofore proposed, is not entirely satisfactory due either to insufcient strength in its housing for long service life or to restriction of the lateral dimensions of its rubber unit with corresponding limit on its ultimate capacity. Of the third type, the draft gear of the present invention not only overcomes the objections to previous such gears but, even in a length ittable into the present standard draft gear pocket, affords at half travel a capacity of about 10,000 foot pounds and at full travel of 21/2 inches a capacity on the order of 50,000 foot pounds. Thus approximating, even in short length, the performance expected of draft gears ittable into the proposed 36 inch pocket, the present draft gear may readily be increased in size to fit such a pocket with corresponding improvement in its already excellent operating characteristics.

I-t, therefore, is the primary object of the present invention to provide an improved housed combined rubber and friction draft gear which, even when made of a size fittable in the present standard draft gear pocket, is of ample strength and capacity at both full and intermediate ranges of travel to meet either present or contemplated service conditions.

Another object of the invention is to provide an improved housed combined rubber and friction draft gear wherein the rubber cushioning unit and the pocket in which it seats are of such arrangement and construction as to afford adequate strength in the housing, while permitting the rubber under compression to flow into openings at the sides of the pocket with consequent increase in the capacity obtainable in the rubber unit.,

An additional object of the invention is to provide an improved housed combined rubber and fiiction draft gear wherein the pocket seating the rubber cushioning unit is partly open at the sides and the plates separating the rubber pads project into the side openings, thereby permitting the pads to flow thereinto under compression.

A further object of the invention is to provide an improved housed combined rubber and friction draft gear wherein thepocket seating the rubber cushioning unit and the plates separating the rubber pads areof such arrangement and construction as to center and guide the plates in theirlongitudinal movement relative to the housing.

vAnother objectief the invention is to provide an improved housed combined rubber and friction draft gear wherein the friction unit, an interposed follower and the several elements of the rubber unit are so interiitted as to inhibit lateral movement of the follower and elemerits relative to the housing.

An additional object of the invention is to provide an improved housed combined rubber and friction draft gear wherein, to facilitate assembly of the gear and initial compression of the rubber unit in assembled position, the follower and elements of the rubber unit are insertible through a slot in the side of the rubber unit containing pocket and an associated plunger, while interlockable with the housing to hold the parts in assembled relation, is insertible with a minimum of canting into an open end of the housing.

Other objects and advantages of the invention will appear hereinafter in the detailed description, be particularly pointed out in the appended claims and be illustrated in the accompanying drawings, in which:

Figure 1 is a side elevational view of a preferred embodiment of the draft gear of the present invention with a portion broken away and shown in a section taken along the lines 1-1 of Figure 2 to more clearly illustrate certain of the details of construction;

Figure 2 isa view of the draft gear of the present invention, partly in plan and partly in a section taken along the lines 2-2 of Figure l;

Figure 3 is Ia vertical sectional view taken along the lines 3 34 of Figure 2; and

Figure 4 is a fragmentary vertical sectional View taken along the lines 4-4 of Figure 3 showing the relation between the rubber cushioning unit and its pocket at substantially full travel of the draft gear.

Referring now in detail to the drawings, in which like reference characters designate like parts, the improved housed combined rubber and fric-tion draft gear of the present invention is comprised of a housing 1 containing a plurality of rubber and friction cushioning units 2 and 3, respectively, at minimum, one cushioning unit of each type. Depending on the number and arrangement of the cushioning units, the housing 1 will be open at one or both ends, that illustrated being at one end 4,

here its front end, closed at its opposite or rear end 5 and containing one rubber cushioning unit 2. and one friction cushioning unit 3.

In the illustrated embodiment, the cushioning units 2 and 3 are arranged in tandem longitudinally of the housing 1 and seat or are contained in a pair of tandemarranged pockets or seats in the housing and longitudinally connected to or opening onto each other, the rubber cushioning unit 2 here being seated or contained in the rear pocket 6 and the friction cushioning unit 3 in the front pocket 7. Defining or closing opposite sides of both pockets are a pair of transversely spaced longitundinal or side walls 8 which are connected at the rear by the transversely extending rear wall 9 of the housing and over the longitudinal extent of the rear pocket 6 have substantially parallel confronting faces 10. The front pocket 7 preferably is contained, as well, over its other pair of opposite sides by a second pair of transversely spaced longitudinal or side walls 11 disposed substantially normal to and connecting the walls 8 of the first pair. However, rearwardly, each of the side walls 11 of this second pair is interrupted by one of a pair of transversely or laterally aligned side openings 12, each opening onto and substantially coextensive longitudinally with but narrower laterally than the rear pocket 6. The lateral restriction or narrowing of the side openings 12 relative to the rear pocket 6 results from the provision at either side of each side opening of a web or rib 13 formed as a continuation of and connecting the associated side wall 11 of the second pair with the rear wall 9 and also connected to and extending inwardly laterally from the adjoining Side of one of the longitudinal walls S of the first pair. Somewhat rectangular in crosssection, the rear pocket 6 thus is closed entirely at one pair of opposite sides by the confronting faces 1i) of the first pair of side walls 8 and at each of its other pair of opposite sides is partly closed by a transversely spaced pair of the webs 13.

Thus far in the description, neither pair of the longitudinal walls 8 or 11 has been stated to be disposed either longitudinally or vertically, simply because the side openings 12 may open either vertically or horizontally of the housing. However7 as will be understood, one pair of the longitudinal walls will be disposed vertically and the other or connecting pair, horizontally. Also, the housing 1 ordinarily will be narrower in one lateral or transverse dimension than the other, to adapt it to be contained between center sills (not shown) in a yoke (not shown) through which draft forces conventionally will be transmitted to the draft gear for cushioning by the cushioning units 2 and 3.

While the friction cushioning unit or units used in the draft gear of the present invention may be of any suitable type, the unit 3 of the illustrated embodiment is similar to that shown in the draft gear of my copending application Serial No. 475,350 tiled December l5, 1954. As in that application, the friction unit 3 here includes a pair of counterpart friction shoes or wedges 14 having a substantially fiat inclined or sloping friction surface T15, the surfaces of the two shoes Baring or diverging toward the front end 4 of the housing and each engaging one of a pair of confronting correspondingly inclined or sloping friction faces 16 formed on one of the pairs of transversely spaced longitudinal walls 8 or 11 of the housing. The friction shoes 14 are urged apart to force or urge their friction surfaces 15 into engagement with the friction faces 16 by suitable resilient or yieldable means, here in the form of an opposed pair of sets of semielliptic leaf springs 17. To interlock the shoes 14 with and limit their forward movement relative to the housing 1, the friction surface 15 of each terminates rearwardly in a transversely or laterally outstanding lip or flange 1b which, in the normal condition of the draft gear, is adapted to overlap laterally a shoulder 19 instanding laterally from the confronting of the longitudinal walls t5 and 11 of the housing and demarking the rear extremity of the friction face 16 thereon.

The draft gear of the illustrated embodiment additionally is similar to that of my cto-pending application, Serial No. 475,350 in containing the friction Shoes 14 within the housing 1 and utilizing a plunger 2% extending or projecting into the mouth or opening 21 at the open end t of the housing for transmitting longitudinal forces to the cushioning units 2 and 3. To avoid the excessive canting of the plunger required during assembly by the use of conventional interlocking lugs at either side for holding the plunger in assembled relation, one or more axially shiftable interlocking pins 22, preferably are employed as the interlocking means at at least one side of the housing in conjunction with a fixed interlocking lug 23 at the other side. While able to be carried by the plunger, the pins 22 and lug 23 preferably are carried by the housing 1. During assembly, the pins are retracted from the mouth 21 of the housing so as to permit the plunger 2t) to be inserted thereinto with a minimum of canting. Thereafter, the pins are driven inwardly laterally to overlap one of a pair of abutments 24 at opposite sides of the inner end of the plunger, the other abutment then being laterally overlapped by the lug 23. Thus locking the plunger 29 in assembled relation, the pins 22 and lug 23 are prevented from interfering with inward longitudinal movement of the plunger relative to the housing by causing them to ride in outwardly opening recesses 25 in either side of the plunger Zd.

Adapted to rub at their front ends 26 against the rear end 27 of the plunger 2t?, the friction shoes 14 are adapted to rub at their opposite or rear ends 2S against the front end or face 29 of a floating follower or follower block 3G contained in the rear pocket t?. As a consequence, not only do the friction shoes 14 transmit longitudinal forces from the plunger 20 through the floating follower 3@ to the rubber cushioning unit 2 against which the rear end or face 31 of the follower bears, so that the illustrated rubber and friction cushioning units act in parallel, but the shoes engender friction at their ends with the plunger and follower, as well as at their friction surfaces 15 with the friction faces 16 on the housing 1, with corresponding increase in the resistance to compression and thus the cushioning capacity of the friction unit.

The rubber cushioning unit 2 of the illustrated embodiment is similar to a conventional rubber cushioning unit, such as employed in a Waugh-Mat Twin Cushion draft gear, in comprising a plurality of rubber spring elements 32 alternating longitudinally with and divided or separated by metal spacer or Separating plates 33, each of the spring elements being formed of a metal center or connecting plate 34 carrying on opposite sides annular or doughnut-shaped rubber pads 35 connected to each other through holes 36 in the connecting plate. Preferably using a pair of rubber pads of 70-75 durometer hardness in each spring element, the rubber cushioning unit 2 is unconventional in several respects. One of the more important of these is the extension of the separating and connecting plates 33 and 34 and the floating follower 3i? into the side openings 12 at opposite sides of the rear pocket 6. Coplanar, respectively with the main portion or body 37 of the plate of which they form a part and the rear face 31 of the floating follower, the side extensions 3@ on the several plates 33 and 34 and tnose 39 on the floating follower, enable the rubber pads 35, which normally -lie well within the lateral extremities of the plates, as shown in Figure 3, to flow not only inwardly into the space afforded by a central hole di) in each pad but also under compression to ow outwardly into the side openings 12 until at full travel of the gear the pads are substantially coextensive with the corresponding outside dimension of the housing as shown in Figure 4.

Another difference is the relation between the plates 33 and 34 and the webs 13 restricting the side openings. Not only do the webs 13 give the housing ample strength for long service life, but their inner faces 41, which preferably ar'e bevelled or slope outwardly in the direction of the side openings 12 to maximize the space available to the rubber cushioning unit 2, are made to serve as guides for the connecting and separating plates 33 and 34 in the longitudinal movements of the latter relative to the housing. To achieve this result with no gouging and a minimum of wear, the several plates, at their corners confronting the webs 13, are provided with preferably integral tabs or ears 42 bent inwardly substantially normal to the bodies 37 of the plates and each disposed substantially parallel to the inner face 41 of the confronting of .the webs 13. While extending or projecting longitudinally of the housing 1, thetabs 42 are limited in their extent relative to the thickness of the intervening rubber pads 35, thus avoiding metal-to-metal contact between the plates, even at maximum travel.

Since both the rear pocket 6 and the several plates 33 and 34, as well as the floating follower 30 are of substantially rectangular or other non-circular cross-section with but slight clearance between the faces defining the pocket and the edges of the plates and follower contiguous thereto, relative rotation of these members is effectively prevented. In addition, it is contemplated to so interrelate the elements of the rubber cushioning unit 2 and associated parts of the draft gear that the rubber cushioning unit and oating follower will be substantially centered in the rear Pocket 6 at all times. To this end, the floating follower 3f? preferably is provided with a plurality of transversely spaced lugs 43 projecting forwardly from its front face 29 and each adapted to ride or slide in a slideway or slot 44 in the rear end 28 of one of the friction shoes 14. Aligned and extending in the direction in which 4the shoes are urged by the interposed leaf springs 17 and thus normal to the pair `of longitudinal walls 8 carrying the friction faces 16, the slideways 44 accommodate relative lateral movement of the shoes and follower in one direction while restraining such movement in a direction normal to the rst. With the floating follower 30 so restrained in lateral movement in at least one direction, the several-spring elements 32 of the rubber cushioning unit 2 are centered relative to each other and the floating follower, as well as the rear wall 9 of the housing 1 defining the rear end of the rear pocket 6, by interrupting each of the pad-confronting faces of the follower and rear wall by a plurality of oifsets, bulges or interruptions. Of the plurality of olsets on each such face, one or more preferably are concave and the other or others convex, so as to engage and bulge each pad both inwardly and outwardly in conformance with the directions of the offsets. Conveniently, four offsets may be provided on each such face with the offsets arranged in a square and diagonally opposite offsets bulged or offset in the same direction. The rubber pads 35 and intervening connecting'plate 34 of each of the spring elements 32 in turn are centered relative to each other by the holes 36 in the connecting plates through which the associated pads are connected or joined.

Constructed in the above manner, the illustrated draft gear is made assembleable by providing at the rear of one of the partly open sides of the rear pocket 6, a slot 46 of sucient cross-section to permit an individual spring element 32 of the rubber cushioning unit 2 to be slid therethrough sideways into the pocket. Of smaller longitudinal cross-section than each of the spring elements 32, the floating follower 30 thus can lbe slid first through the slot and moved to the front end of the pocket, whereafter, in succession, a spring element and a separating plate are slid individually into the rear pocket, until all of the components of the rubber cushioning unit 2 are seated therein.

Next, the friction shoes 14 are applied'through the mouth 21 of the housing 1 and, after the shoes have been forced rearwardly to bring their outstanding anges 18 into register with the instanding shoulders 19 on the housing, the leaf springs are inserted through the mouth 21 between the shoes to force :the latter apart and into interlocking relation with the housing. Entailing rearward shifting of the floating follower 30, the application of the friction shoes also serves to place the rubber cushioning unit 2 under initial or precompression. Finally, the plunger 20 is inserted through Ithe mouth 21 of the housing 1 and locked in assembled relation by the pins 22 and lug 23. If, as in the illustrated embodiment, the front end of the plunger is considerably narrower than the draft gear pocket (not shown) into which the draft gear is adapted to be inserted, a front follower (not shown) will be needed between the plunger and the butt (not shown) of an associated coupler (not shown) so as to enable the draft gear to react in draft against front draft lugs (not shown) at the front end of the draft gear pocket.

From the above detailed description, it will be apparent that there has been provided an improved housed combined rubber and friction draft gear which is of rugged construction and long service life and has exceptional operating characteristics. It should be understood that the described and disclosed embodiment is merely exemplary of the invention and that all modifications are intended to be included which do not depart from either the spirit of the invention or the scope of the appended claims.

What is claimed is:

l. A draft gear comprising a housing open at at least one end, a friction cushioning unit in said housing, a rubber cushioning unit in said housing and formed of alternating plate means and rubber pad means, said cushioning units each seating in one of a plurality of connected pockets in said housing, side openings in said housing at opposite sides of and substantially coterminous longitudinally with and restricted laterally relative to the pocket containing said rubber cushioning unit, and side extensions on and extending substantially parallel to said plate means into said side openings, said rubber pad means on application of a longitudinal force thereto through said open end of said housing flowing outwardly over said extensions into said side openings.

2. A draft gear comprising a housing open at at least one end, a friction cushioning unit in said housing, a rubber cushioning unit in said housing and formed of alternatnig plate means and rubber pad means, said cushioning units each seating in one of a plurality of connected pockets in said housing, side openings in longitudinal walls of said housing at opposite sides of the pocket containing said rubber cushioning unit and each restricted laterally relative .to said pocket by web portions of the associated longitudinal wall, side extensions on said plate means and projecting into said side openings, and tab means on said plate means and each confronting and disposed substantially parallel to an inner face of `one of said web portions for guiding said plate means on longitudinal movement thereof relative to said housing, said rubber pad means on application of a longitudinal force `thereto through said open end of said housing flowing outwardly over said extensions into said side openings.

3. A draft gear comprising a housing open at at least one end, a friction cushioning unit in said housing, a rubber cushioning unit in said housing and formed of alternating rubber pads and metal plates, said cushioning units each seating in one of a plurality of connected pockets in said housing, side openings in longitudinal walls of said housing at opposite sides of the pocket containing said rubber cushioning unit and restricted laterally relative to said pocket by web portions of said walls, side extensions 0n and substantially coplanar with the body of each of said plates and projecting from opposite sides thereof into said side openings, tabs on each of said plates and each disposed substantially normal to the body thereof and substantially parallel to an inner face of a confronting of said web portions for guiding said plates on longitudinal movement thereof relative to said housing, and offsets on pad confronting faces of certain of said plates for correspondingly bulging adjoining of said pads and centering said pads laterally relative to said housing, said rubber in said pads on application of a longitudinal force thereto through said open end of said housing flowing outwardly over said extensions into said side openings.

4. A draft gear comprising a housing open at at least one end, a friction cushioning unit in said housing, a rubber cushioning unit in said housing and formed of alternating rubber pads and metal plates, said cushioning units each seating in one of a plurality of connected pockets in said housing, side openings in longitudinal walls of Said housing at opposite sides of the pocket con4 taining said rubber cushioning unit and restricted laterally relative to said pocket by web portions of said `walls, side extensions on and substantially coplanar with the body of each of said plates and projecting from opposite sides thereof into said side openings, tabs on each of said plates and each disposed substantially normal to the body thereof and substantially parallel to an inner face of a confronting of said web portions for guiding said plates on longitudinal movement thereof relative to said housing7 and interruptions in pad confronting faces of said plates and engaging said pads for centering said pads laterally relative to said housing, said rubber in said pads on application of a longitudinal force thereto through said open end of said housing flowing outwardly over said extensions into said side openings.

5. A draft gear comprising a housing open at at least one end, rubber and friction cushioning units in said housing and each seating in one of a plurality of connected pockets therein7 said rubber unit including a plurality of rubber spring elements arranged in alternation with separating plates and each formed of rubber pads sandwiching and connected through holes in a connecting plate, side openings in longitudinal walls of said housing at opposite sides of and each substantially coterrninous longitudinally with and restricted laterally relative to the pocket containing said rubber cushioning unit, a floating follower in said last-named pocket between said friction and rubber cushioning units, said plates and follower having Side extensions projecting substantially parallel thereto into said side openings, and means on said plates and each extending substantially parallel to a confronting face of said last-named pocket for guiding said plates in longitudinal movement thereof relative to said housing, and means intertting said friction unit, follower, spring elements, separating plates and a rear wall of said housing for centering the rubber cushioning unit relative to said housing, said rubber in said pads on application of a longi- 8 tudinal force thereto through said open end of said housing flowing outwardly over said extensions into said side openings.

6. A draft gear comprising a housing open at at least one end, rubber and friction cushioning units in said housing and each seating in one of a plurality of connected pockets therein, said friction unit including a pair of counterpart friction shoes and interposed leaf spring means yieldably urging friction surfaces on said shoes into frictional engagement with friction faces carried by said housing, said rubber cushioning unit including a plurality of rubber spring elements arranged in alternation with separating plates and formed of rubber pads sandwiching and connected through holes in a connecting plate, side openings in longitudinal walls of said housing at opposite sides of and each substantially coterminous longitudinally with and restricted laterally relative to the pocket containing said rubber cushioning unit, a floating follower in said last-named pocket between said friction and rubber cushioning units, said plates and follower having side extensions projecting substantially parallel thereto into said side openings, means on said plates and each extending substantially parallel to a confronting face of said last-named pocket for guiding said plates in longitudinal movement thereof relative to said housing, a plurality of lugs on and projecting from a front face of said follower and each slidable in one of a pair of aligned transversely directed slide-ways each in a confronting end of one of said shoes, and a plurality of transversely spaced offsets in each of the pad-confronting faces of said follower, separating plates and. rear wall of said housing and correspondingly bulging said rubber pads for centering said rubber unit relative to said housing. said rubber in said pads on application of a longitudinal force thereto through said open end of said housing flowing outwardly over said extensions into said side openings.

7. A draft gear comprising a housing having a closed rear end and an open front end, a rear pocltet in and closed at the rear by the rear end of said housing, a front pocket in said housing interposed between and opening onto said open front and rear pocket, a friction cushioning uru't within said front pocket, plunger projecting into said front pocket, pin means carried by said housing and drivable laterally thereof into laterally overlapping relation with said plunger for lool/.ing said plunger in assembled relation, a rubber cushioning unit in said rear pocket and formed of alternating plate means and rubber paid means, side openings in said housing at opposite sides of and substantially coterminous longitudinally with and restricted laterally relative to said rear pocket, and side extensions on and extending substantially parallel to said plate means into said side openings, said rubber pad means on application of a longitudinal force thereto flowing outwardly over said extensions into said side openings.

No references cited. 

